1. Technical Field
The present invention is directed to a semiconductor device, and especially, to a string select line (SSL) of a three-dimensional memory array and the method of fabricating the same.
2. Description of Related Art
A non-volatile memory can maintain the stored data even after the power is off, and thus the non-volatile memory has become a mandatory memory in many electronic products, so as to ensure the normal operation when the electronic products are booted.
Together with the size reduction of electronic devices, dimensions of the memory containing memory cell arrays are decreased. However, the existing photolithography technology imposes restrictions on the size reduction of a normal two-dimensional memory cell array (e.g., reduction of the distance between adjacent memory cells).
A technique of stacking multiple films and then constructing memory cells are developed by researchers. This technique, the so-called “three-dimensional memory array,” has a potential to achieve an immense storage capacity and a low cost per unit bit. Unfortunately, the process of forming the current three-dimensional memory cell array is rather complicated, and the size reduction of the three-dimensional memory cell array is still subject to the existing photolithography technology.